MTMR2 and Charcot-Marie-Tooth disease type 4B1: Mutations in MTMR2 cause Charcot-Marie-Tooth disease type 4B, which features a generalized loss of large myelinated nerve fibers and focally folded myelin sheaths giving rise to inadequate nerve signaling to muscles, resulting in muscle weakness and atrophy (Volpatti et al., 2019).